1. Field of the Invention
The present invention relates to a soft magnetic alloy film for use in a magnetic head or the like.
2. Description of the Related Art
In the field of a magnetic recording, there is a demand for magnetic head materials which have a high saturation magnetic flux density (Bs) and which are therefore capable of coping with a recording medium, such as a magnetic tape, having a high coercive force and, hence, a high recording density.
Conventional soft magnetic materials (films) having a high saturation magnetic flux density include Fe-Si-Al alloy (sendust). In recent years, however, amorphous alloy films mainly composed of a ferromagnetic metallic element Co have been developed.
Further, alloy films (Fe-C and Fe-Si films), which are mainly composed of Fe and which consist of crystallite, have recently been proposed. Such alloy films have a high saturation magnetic flux density and excellent soft magnetic characteristics because the adverse effects of the crystal magnetic anisotropy of Fe (to the soft magnetic characteristics) are alleviated by the refining of the crystal grains.
Recently, the apparatuses with a magnetic head incorporated therein have been reduced in size as well as in weight. Further, such apparatuses are often subjected to vibrations caused by transportation and used under unfavorable conditions. Hence, there is a demand for magnetic heads which have excellent magnetic characteristics, which are abrasion resistant to the magnetic tape, which withstand temperature or corrosive atmosphere, i.e., unfavorable environments, and which are highly resistant to vibrations. These require that a glass bonding process be employed to form a gap or incorporate the magnetic head into a casing. This in turn requires that the magnetic head be made of a material which can withstand the high temperatures which are reached during the glass bonding process.
However, the conventional soft magnetic alloy film sendust has a saturation magnetic flux density of about 10000 G (gauss), which is unsatisfactory to cope with the demands of a magnetic tape having a high recording density. The Co type amorphous alloy film have a high saturation magnetic flux density of 13000 G or above. However, in order to provide an amorphous alloy having a high saturation magnetic flux density, an amount of amorphous alloy forming element employed, such as Ti, Zr, Hf, Nb, Ta, Mo and W, must be decreased. Decrease in the amount of amorphous alloy forming element causes the stability of the amorphous structure to be reduced, thereby causing the resultant alloy to be unable to withstand the temperature required for glass bonding process (about 500.degree. C. or above).
Furthermore, the above-described alloy films (Fe-C, Fe-Si and so on), composed mainly of Fe and consisting of fine crystals, generate growth of the crystal grains at high temperatures and therefore deterioration occurs in their soft magnetic characteristics (at 400.degree. C. at maximum in the case of Fe-C alloy). This makes these alloy films unsuitable for glass bonding.